miércoles, 15 de mayo de 2019

What is Von Willebrand Disease?

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Von Willebrand disease is the most common inherited bleeding disorder that affects approximately 1% of the population, although not everyone is symptomatic. The disease can also be acquired later in life as a result of other health conditions.

It involves a deficiency of Von Willebrand factor (vWF) that is responsible for platelet adhesion and is characterized by symptoms of bruising and bleeding from mucous membranes.

Types

There are four phenotypes of Von Willebrand disease:

Type 1 is the most common type and involves reduced levels of vWF and is associated with mild bleeding.

Type 2 involves vWF with abnormal structure and resulting function. The symptoms of this type vary between cases with different bleeding patterns.

Type 3 is characterized by the absence, or near absence, of vWF. Patients affected by this rare type have symptoms similar to moderate to severe hemophilia.

Platelet type, also known as pseudo type, involves abnormality of the platelets rather than the vWF. In functionality and symptoms, it is similar to type 2.

Pathophysiology

Von Willebrand disease is caused by a defect in the gene responsible for vWF production. The genetic fault can be inherited from either parent that carries the gene, who may or may not be symptomatic.

While most types are follow an autosomal dominant inheritance pattern, type 3 is inherited in an autosomal recessive pattern, which means both parents need to pass on defective gene for the child to be affected by this type.

Symptoms

Some people with Von Willebrand disease, particularly those affected by type 1, do not notice any symptoms due to their mild nature. Symptoms of the disease may include:

Bruising easily
Bleeding from mucous membranes (e.g. gums, nose, gastrointestinal tract)
Prolonged bleed following minor cuts
Post-operative bleeding excess
Heavier menstruation for women

As these symptoms usually only present when there is some cut or injury to the body, most people with the disease lead unaffected lives for the majority of the time. For those with more severe symptoms, treatment can help to manage symptoms a great deal.

Diagnosis

Many people with Von Willebrand disease will not be diagnosed, as they do not suffer from notable symptoms. If symptoms are evident and it is possible deficiency of vWF could be a causative factor, referral to a hematologist is justified.

Family history of Von Willebrand disease should be discussed, as it is a hereditary condition and affected family mothers can help in making a diagnosis. Confirmation of diagnosis can be reached with blood tests, which may needed to be conducted on several occasions, as the level of vWF can vary over time.

Management

In mild cases of Von Willebrand disease, pharmacological treatment may not be necessary as small lifestyle changes may be sufficient to avoid situations that lead to bleeding or bruising.

In more severe cases, significant lifestyle changes may be necessary. If bleeding poses a serious risk, contact sports and other situations that may result in injuries should be avoided.

The first-line treatment in desmopressin, which is available as a nasal spray or injection. Side effects may include facial flushing, palpitations, hypotension, headache and fluid retention.

Alternative treatments include tranexamic acid, which is available as an oral dose or as an injection, and Von Willebrand factor concentration. This is the factor purified from donated blood that is administered intravenously to provide and immediate effect.

Some medications may worsen symptoms as they reduce the blood’s ability to clot even further, including common non-steroidal anti-inflammatory drugs (NSAIDS) like ibuprofen and aspirin.

Patients that need surgery or to have dental work done are likely to experience excessive bleeding due to the surgical incisions. It is imperative that relevant health professions are informed of the condition and appropriate preventative measures, such as pharmacological treatment prior to the operation, are adhered to.